The objectives of this research are as follows: To delineate the ultrastructure of the normal microcirculation in human skin. Microcirculation is defined to include both blood and lymphatic vessels. Normal skin will be studied by light and electron microscopy through reconstruction techniques to map out the configurations of the microcirculation in the papillary and reticular dermis. Psoriatic lesions in various stages of development and regression will be studied by electron microscopy to determine the nature of the vascular abnormalities precede or come after the epidermal hyperplasia of the disease. Telangiectasias of various types which indicate the presence of a systemic disease will be studied to determime their three dimensional configurations by cleared whole mounts of skin. The type of abnormal vessel present in the malformation will be studied by electron microscopy. BIBLIOGRAPHIC REFERENCES: Braverman, I. M. and Yen, A. Demonstration of immune complexes in spontaneous and histamine induced lesions and in normal skin of patients with leukocytoclastic angiitis. J. Invest. Derm. 64: 105-112, 1975.